Buggy code:
@ SuppressWarnings ( "unchecked" ) public class GenericTypeConverter implements TypeConverter , ConverterRegistry { private final Map sourceTypeConverters = new HashMap ( ) ; private TypeConverter parent ; public TypeConverter getParent ( ) { } public void setParent ( TypeConverter parent ) { } public void add ( Converter converter ) { } public void add ( ConverterFactory < ? , ? > converterFactory ) { } public void removeConverter ( Class < ? > sourceType , Class < ? > targetType ) { } public void removeConverterFactory ( ConverterFactory < ? , ? > converter ) { } public boolean canConvert ( Class < ? > sourceType , Class < ? > targetType ) { } public boolean canConvert ( Class < ? > sourceType , TypeDescriptor < ? > targetType ) { } public < S , T > T convert ( S source , Class < T > targetType ) { } public < S , T > T convert ( S source , TypeDescriptor < T > targetType ) { } ConversionExecutor getConversionExecutor ( Class sourceClass , TypeDescriptor targetType ) throws ConverterNotFoundException { Assert . notNull ( sourceClass , "The<seq2seq4repair_space>sourceType<seq2seq4repair_space>to<seq2seq4repair_space>convert<seq2seq4repair_space>from<seq2seq4repair_space>is<seq2seq4repair_space>required" ) ; Assert . notNull ( targetType , "The<seq2seq4repair_space>targetType<seq2seq4repair_space>to<seq2seq4repair_space>convert<seq2seq4repair_space>to<seq2seq4repair_space>is<seq2seq4repair_space>required" ) ; if ( ( targetType . getType ( ) ) == null ) { return NoOpConversionExecutor . INSTANCE ; } TypeDescriptor sourceType = TypeDescriptor . valueOf ( sourceClass ) ; if ( sourceType . isArray ( ) ) { if ( targetType . isArray ( ) ) { return new ArrayToArray ( sourceType , targetType , this ) ; } else if ( targetType . isCollection ( ) ) { if ( targetType . isAbstractClass ( ) ) { throw new IllegalArgumentException ( ( ( ( "Conversion<seq2seq4repair_space>target<seq2seq4repair_space>class<seq2seq4repair_space>[" + ( targetType . getName ( ) ) ) + "]<seq2seq4repair_space>is<seq2seq4repair_space>invalid;<seq2seq4repair_space>cannot<seq2seq4repair_space>convert<seq2seq4repair_space>to<seq2seq4repair_space>abstract<seq2seq4repair_space>collection<seq2seq4repair_space>types--" ) + "request<seq2seq4repair_space>an<seq2seq4repair_space>interface<seq2seq4repair_space>or<seq2seq4repair_space>concrete<seq2seq4repair_space>implementation<seq2seq4repair_space>instead" ) ) ; } return new ArrayToCollection ( sourceType , targetType , this ) ; } else if ( targetType . isMap ( ) ) { if ( sourceType . getElementType ( ) . equals ( String . class ) ) { <START_BUG> return null ; <END_BUG> } else { return null ; } } else { return null ; } } if ( sourceType . isCollection ( ) ) { if ( targetType . isCollection ( ) ) { return new CollectionToCollection ( sourceType , targetType , this ) ; } else if ( targetType . isArray ( ) ) { return new CollectionToArray ( sourceType , targetType , this ) ; } else if ( targetType . isMap ( ) ) { if ( sourceType . getElementType ( ) . equals ( String . class ) ) { return null ; } else { return null ; } } else { return null ; } } if ( sourceType . isMap ( ) ) { if ( targetType . isMap ( ) ) { return new MapToMap ( sourceType , targetType , this ) ; } else if ( targetType . isArray ( ) ) { if ( targetType . getElementType ( ) . equals ( String . class ) ) { return null ; } else { return null ; } } else if ( targetType . isCollection ( ) ) { if ( targetType . getElementType ( ) . equals ( String . class ) ) { return null ; } else { return null ; } } else { return null ; } } if ( targetType . isArray ( ) ) { return null ; } if ( targetType . isCollection ( ) ) { return null ; } if ( targetType . isMap ( ) ) { return null ; } if ( sourceType . isAssignableTo ( targetType ) ) { return NoOpConversionExecutor . INSTANCE ; } Converter converter = findRegisteredConverter ( sourceType . getType ( ) , targetType . getType ( ) ) ; if ( converter != null ) { return new StaticConversionExecutor ( sourceType , targetType , converter ) ; } else { return null ; } } private List getRequiredTypeInfo ( Object converter ) { } private Class getParameterClass ( Type parameterType , Class converterClass ) { } private Map getSourceMap ( Class sourceType ) { } private Converter findRegisteredConverter ( Class < ? > sourceType , Class < ? > targetType ) { } private Map getConvertersForSource ( Class sourceType ) { } private Converter getConverter ( Map converters , Class targetType ) { } private Converter getConverterImpl ( Map converters , Class currentClass , Class targetType ) { } }

Fix:
return new StringArrayToMap ( sourceType , targetType , this ) ;